Process for regulating steam generators and automatic feed systems for such generators



March 9, 1948.

PROCESS FOR REGU FEED SYSTEMS FOR EU I Original Filed Feb. 28, 1941 JLOUMIET ET LATING STEAM G LAVIGNE 2,437

ENERATORS AND AUTOMATIC CH GENERATORS 3 Sheets-She etl fivenlbr Jeanloam/1e? 7 Lav/gas fliiorneys March 9, 1948- J. LOUMIET .ET LAVIGNE 2437,327

PROCESS FOR REGULATING STEAM GENERATORS AND AUTOMATIC FEED SYSTEMS FORSUCH GENERATORS I Original Filed Feb. 28, 1941 3 Sheets-Sheet 2Afiornegi J. LOUMIET ET LAVIGNE 2,437,327 PROCESS FOR REGULATING S March9, 1948.

TEAM GENERATORS AND AUTOMATIC FEED SYSTEMS FOR SUCH GENERATORS OriginalFiled Feb. 28, 1941 3 Sheets-Sheet 5 Inveniar Jed/7 loam/e7 7 avg/7eAttorneys Patented Mar. 9, i948 PROCESS FOR REGULATING STEAM GEN-ERATORS AND. AUTOMATIC FEED SYS- TEMS FOR SUCH GENERATORS Jean Loumietet Lavigne, Itabo, Cuba Original application February 28, 1941, SerialNo. 380,987. Divided and this application April 8,

1943, Serial No. 482,284.

In Cuba March 9,

9 Claims. (Cl. 122-448) The present invention is a division of my PatentNo. 2,377,254 and relates to an apparatus and process for automaticallyregulating steam generators or boilers and the feed devices there- Thesystem of the present invention comprises basically in establishing, asa first approximation in the regulation of a steam generator,proportional feed supplies of water, fuel and air, in accordance withone of the limiting requirements (maximum or minimum) of efliciency ofthe generator and in imparting by a complementary regulation, a finaladjustment to that original or primary regulation, so as to adapt it atevery moment to the exact needs of the steam generator. Imperfection inthe functioning of the steam generator is manifested as to the supply ofwater, by the variations of the water level in the generator and as tothe supply of heat (fuel and air) by the variations of steam pressure.These variations in the steam generator are utilized to automaticallyproduce the compensat ing regulations that will rectify the deficiencyobserved.

The system of the present invention complies with the followingrequirements: (1) The water supplied at every moment compensates for theconsumption of steam taking place. (2) Fuel and air constituting themediums for producing heat is supplied in relation to the steamconsumption or to the water injected in a proportion exactlycorresponding at every moment to the operating efiiciency of the steamgenerator.

The efficiency of the steam generator is variable according as theproduction of steam for the generator varies. Within the conditions ofindustrial operation, it decreases slightly as the production increases.The decrease of efilciency becomes more rapidly accelerated thantheincrease in-the steam production, and that acceleration is alsovariable, increasing as saidsteam production increases.

In accordance with the present invention, the original supply of feedwater and fuel in a given proportion corresponding to the maximum orminimum of efliciency of the steam generator is obtained by means of adrive motor in the form of a steam engine, electric motor or the likeand of feed devices of constant volumetric yield perated from said drivemotor at speeds proportional to the speed of said motor. Primaryregulation of the feeds to the generator would beobtained by means ofthe single regulation of the drive motor which drives the water feedpump, the petroleum or other fuel feed pump and variations.

the air pump or blower supplying combustion air. The speed of the drivemotor is regulated in such a way that by the primary regulation, thesupply of fuel and of air produced corresponds to the exact needs of theboiler, while the supply of water only approximates the real need of thegenerator. This primary regulation through regulation of the speed ofthe drive motor is effected in response to variations in the steampressure in the generator.

The exact requirements of water feed in relation to the feeds ofcombustion air and fuel are variable in accordance with theelficiency ofthe steam generator. These exact requirements are met by a secondary orcomplementary regulation in the rate of feed of the water in relation tothe feed of the combustion elements (fuel and air).

This secondary regulation is effected automatically in accordance withthe water level in the water drum of the steam generator.

In accordance with the present invention, primary regulation of thedrive motor is effected in accordance with variations in the steampressure alone independently of variations in the water level, and thesecondary regulation of the feed water supply is effected in accordancewith variations in the water level in the steam generator aloneindependently of steam pressure Also, the regulations are suspended ashort interval after the corresponding regulating steam pressure orwater level begins to return towards normal.

As another feature, the complementary regulation of feed water iseifected in a manner to compensate for the decrease in efficiency of thesteam generator at a progressively increasing rate as said steamconsumption increases after the steam consumption reaches above apredetermined limit.

Various other features of the invention will be apparent from thefollowing particular description and from an inspection of theaccompanying drawings, in which Fig. 1 is a schematic view of a form ofapparatus in accordance with the present invention for automaticallyregulating a steam generator and various feed devices for such agenerator and for carrying out the process of the present invention;

Fig. 2 is a schematic view of another form of apparatus in accordancewith the present invention for automatically regulating a steamgenerator and feed devices for such a generator and for carrying out amodified form of process of the present invention;

Fig. 3 is a sectional perspective of one of the valves controlling theby-pass between the discharge and inlet of the water feed pump in theapparatus of Fig. 2;

Fig. 4 is another schematic layout showing a modified apparatus inaccordance with the present invention for automatically regulating asteam generator and feed devices therefor and for carrying out amodified form of process of the present invention; and

Fig. 5 is a schematic layout showing the secondary regulation of thewater feed pump by means of two valves connected in parallel.

Referring to Fig. 1 of the drawings, there is provided a boiler or steamgenerator C, a drive motor shown in the form of a steam engine Ci havinga steam inlet valve V in a supply line T and a water feed pump Ba whichis shown of the centrifugal type and which feeds water to the drum ofthe boiler by a supply line Ta. The water feed pump But is shown drivenfrom the engine Cl by a belt drive.

The engine Ci also drives a fuel pump Bp shown of the reciprocating typeoperated from the crank shaft of the engine Cl,as shown more fully inFigs. 4, 5 and 6 of the parent Patent 2,377,254. lihis fuel pump Bp isshown delivering fuel to three fuel burners Q ofthe boiler C by means ofthe fuel supply line b.

The engine Ci also drives a blower Vn, as for example, by a belt driveas shown, to deliver combustion air to the burners Q of the boiler Cthrough an air duct A.

The three boiler feeding devices Ba, 18p and Vn are operated by the samesteam engine Cl and the speed of that engine is regulated throughvariations in the boiler pressure so as'to maintain said pressureconstant. For that purpose, the extent of opening of the steam inletvalve V for the engine is controlled from an electric motor m through aspeed reduction gearing shown comprising a worm and worm wheel, the wormwheel being aiiixed to a sleeve having a threaded connection with thevalve stem, so that rotation of said worm wheel causes axial movement ofsaid stem and corresponding opening and closing movement of the valve.The construction of the valve V and the manner of its operation by themotor m is similar to that shown in Fig. 2 of my Patent 2,377,254.

The motor m is regulated through a compressed air manometer M operatingonly in accordance with boiler pressure variations to provide a primaryregulation of the system operable only in accordance with saidvariations independently of variations in the water level. Thismanometer M is similar to that described in my Patent 2,377,254 andshown in Fig. 3 of said patent and operates as indicated in said patentthrough electrodes 1), k, 'r, 7, Z, and w, connections therefrom to acoil switch box Em and connections 3 and d from said box to the motor m.This manometer M controls the motor m and is operable to suspend theoperation of the motor m a short interval after the steam pressurebegins to return towards normal, thereby assuring the opening or closingof the valve V to the proper extent to eifect return towards normalwithout any substantial overrun of said valve.

By means of the primary regulation described, the speed of the drivemotor or engine Cl is varied, so that the speeds of all the feedingdevices Ba, Bp and Vn are varied in unison; while maintaining therelative rates of feed of said feeding devices substantially constant,thereby maintaining the pressure of the boiler substantially constant.

There is obtained by this first regulation, a supply of. fuel orpetroleum corresponding at every moment to the needs of the boiler and asupply of feed water which would exactly represent the supply requiredby the boiler if operating at that moment under the worst or maximumefiiciency conditions within its operating limits. Since, in realpractice, the efficiency of the generator varies, it is necessary bysecondary regulationto adjust continuously the supply of feed water fromthe approximation obtained through primary regulation.

Secondary automatic regulation is effected responsive only to variationsin the water level in the boiler alone and independently of steampressure variations for varying the rate of feed of the water inrelation to the feed of the combustion elements, to maintain thereby thewater levelin theboiler substantially constant. For that purpose, thereis shown in the feed water supply line To. to the boiler, a valve Va,controlled by an electric motor in which in turn is governed by theregulating gauge N. This gauge N is operated in response to thewater-level variations in the boiler and is similar to that described inmy Patent 2,377,254 and illustrated in Fig. 2 .therein. This gauge N haselectrodes 0, b, a and 01 connecting into a coil and switch boxEn whichis fed by power lines 5 and 5 and which controls the motor m throughconnections 5, 6, i and 8. The gauge N functions so that the operationof the electric motor is suspended a short interval after. the waterlevel begins to return towards normal as indicated in the aforesaidpatent.

In the construction of Fig. l, the water leaving the feed pump isregulated by regulating the cross-section of the discharge. The waterleaving the feed water pump may be regulated by subtracting some of thewater or may be regulated in any other manner as will be described.

For every'value of steam consumption, there is a corresponding boilereiiiciency which is theoretically fixed, and which varies a little, asfor example, when the boiler is not clean or when the humidity of theair varies. According to .the steam consumption, there is acorresponding predetermined velocity of the motor that generates all theoriginal feeding rates. It is possible to establish a first regulationby changing the original water rate and adapting it automatically to theefiiciency' variations, such regulation being effected by virtue of thevelocity of the motor driving all the feeding mechanisms. Thewater rateregulated in that'manner may correspond exactly to the needs of theboiler with a slight margin in excess, assuming that the actualefficiency of the boiler was the one desired according to its steamconsumption. The water rate obtained in this manner willcloselyapproximate the required rate for-the boiler, so that the secondcomplementary regulation based on the water level variation in theboiler will have to provide only for the slight difference. Therefore,the maximum effect of this supplementary regulation would be greatlylimited, thereby effecting an important advantage.

Figs. 2 and 3 show a processand construction for producing this result.In these drawings, Cl indicates a steam motor or engine for operatingthe fuel and air pumps (not shown), and also the water feed pump vBahaving an inlet Su and an outlet Di. A by-pass connecting this inlet Suand outlet Di is governed by means of valves Va and V'a connectedtherein in series. The valve Va is governed by virtue of the speed ofthe engine Ci through a centrifugal governor Re connected to said engineby suitable transmissions (not shown). The vertically movable part ofthis governor Re carries a rack Cn meshing with a pinion Pi driving apinion Pi through a belt. This pinion Pi meshes with a second rack Cmconnected to the stem of the valve V'a.

As the velocity of the engine Cl increases, the aperture of the by-passvalve Va increases, so that the water rate with respect to the fuel isdecreased in accordance with the decrease in efli'ciency of the steamgenerator C. The valve Va does not begin to decrease the water feeduntil the boiler efiiciency begins to vary to a substantial extent, i.e., until the boiler efiiciency corresponds to that which the boiler haswhen its steam consumption is double that of the boiler at its maximumefiiciency. The valve member of the valve Va is constructed to eifectthis operation.

The opening of the valve Va must increase with progressive accelerationas the velocity of the engine Cl increases, i. e., the load increases.While the engine speed is increasing, the steam boiler efficiency isdecreasing with progressive acceleration. The lower section of the valvemember Va is tapered as shown, so that said valve is opened withprogressive acceleration as said valve member moves upwardly. In anycase, the shape of this valve member is designed to correspond to theefficiency variations of the boiler as the steam production increases.

Valve Va. completes the regulation of the water feeding, and is operatedby virtue of the water level variations in the boiler in a manneralready described in connection with the construction of Fig. 1.

Figs. 4 and 5 show a similar process and construction, but in connectionwith a centrifugal feed water pump Ba instead of a reciprocating pump.In the modified construction shown in Fig. 4, the valve Va operated inaccordance with water level variations is located in the outlet pipe D2of the pump Ba behind the valve V'a, but if desired, can be located insaid outlet pipe ahead of the valve Va. 7

In Fig. 5, the outlet of the centrifugal pump Ba has two parallelbranches merging into the pipe Di and containing the valves V'a. and Varespectively. Although both branches have been shown of equaldimensions, in actual practice it would be desirable to increase thedimensions of the branch regulated by valve V'a in relation tothe branchregulated by valve Va, because the importance of the first regulation isgreater than that of the second.

In the form of the invention shown in Figs. 2 and 3, the by-pass valveV'a may be constructed with a cylindrical section and with a lowertapering section as described, and may be arranged so that as long asthe speed of the engine does not reach double the speed corresponding toconditions of greatest efficiency of the boiler, the proportion ofsubtracted or by-passed supply shall be substantially constant andstarting from the moment at which said engine speed increases above saidlimit, said subtracted proportion shall increase with said speed at agreater rate than the speed of the engine and with increasingacceleration as said engine speed rises above said limit. Thisprocessfeature of the present invention may be carried out by the constructionsof Figs. 2 and 3 described or by any other suitable construction. Forexample, the valve member of valve Va in Figs. 2 and 3 may be ofuniformly tapering dimensions and operated from the engine ballgovernors through a cam having a section of uniform radius operable tomaintain said valve member against movement while the engine isoperating below the double speed limit of maximum boiler efficiency andhaving a section progressively decreasing in radius and operable beyondsaid engine speed limit to open said valve with progressively increasingacceleration to progressively increase the rate of feed water by-passedor subtracted. The shape of this variable cam section is designed tocorrespond to the efliciency variations of the boiler as the steamproduction increases beyond the limit determined by the operation of theengine at twice the speed of maximum efficiency of the boiler.

Instead of controlling the by-pass valve Va by the cam arrangementdescribed, the valve controlled by the cam may be the discharge valve Vaof the feed water pump as shown in Fig. 5. In that case, the cam wouldbe constructed with a progressively radially increasing section beyondits radially uniform section, operable to close said valve at aprogressively increasing rate to effect decrease in the rate of feed ofwater into the boiler at the desired progressively decreasing rate. Thesecondary or final regulation which is effected by means of the waterlevel variations in the boiler would be preferably effected in a pipeconnected in parallel with the pipe containing the valve V'a, as shownin Fig. 5.-

I claim:

1. An apparatus for regulating steam boilers of the type provided with awater drum to maintain the water level and the steampressuresubstantially constant, comprising means for feeding combustion elementsto the boiler, means for feeding water to the boiler, a single motor fordriving said feeding means, means automatically operable only inaccordance with variations in the steam pressure alone and independentof variations in the water level for varying the speed of said drivemotor to vary the speed of all of said feeding means in unison, whilemaintaining the relative rates of feed of said feeding means constant tothereby maintain said pressure substantially constant, meansautomatically responsive only to variations in the wate level in saidboiler alone and independently of steam pressure variations for varyingthe rate of feed of the water in relation to the feed of the combustionelements, to thereby maintain the water level substantially constant,and means for suspending the operation of said varying means a shortinterval after the corresponding regulating steam pressure or waterlevel begins to return towards normal.

2. A process for'regulating steam generators of the type provided with awater drum and having as auxiliary units a fuel supply mechanism, a

combustion air supply mechanism and a water feed supply mechanism, whichcomprises the steps of operating said fuel supply mechanism and said airsupply mechanism as a, group in relation to the water feed supplymechanism and at predetermined relative rates to establish apredetermined-proportion between the fuel supply and the air supply,operating all of said mechanisms from a single drive'motor, regulatingsaid drive motor in accordance with the steam pressure variations in thegenerator to maintain the steam pressure in said generatorsubstantially: constant;

and effecting; supplementary regulation of thewater feed rateinlrelation to therates of fueland air supply in accordance Withthewatenlevel variations in the water drum'to adapt said water'- feed rateto'the actual efficiency of the generator, and to maintain thewaterlevel in'said drum substantially-constant, saidsupplementary 'regula--tion being efiected-Wi-thout afiectingthe rates-oi fuel and air supplyas determined by the regulationof said drive motor and while maintainingsaid latter rates at said predetermined proportion, both of saidregulations being effected slowly'and progressively, and being stopped aslightinterval after the corresponding steam pressure or Water levelbegins its return movement towards normal;

3, A process for regulating steam-generators of the type provided with aWater drum and having.

as auxiliaryunits a, fuel supply mechanism, acombustion air supplymechanism and a wa'ter feed supply mechanism, whichcomprises the stepsof operating said fuel supply mechanism and said air supply mechanism asa group in relation to the Water feed supply mechanismand atpredetermined relative rates to establish a" prede-- termined proportionbetween the fuel supply and the air supply, operating all'of saidmechanisms from a single drive motor, regulating" saiddrive motor inaccordance With the steam pressure variations in the generator tomaintain the steam pressure in said generator substantially constant,and effecting supplementaryregulation ofthe water feed rate in relationto the rates of fuel and air supply in accordance with the Waterlevel-var iations in the Water drum to adapt said water feed rate to theactual efficiency of the generator, and to maintain the Water'levelinsaid drum'substantially constant, said-supplementary regulation beingeffected without afiectingsthe rates :01 fuel and air supply asdetermined by the regulation of said. drive motor and While maintainingsaid latterrates at said predetermined proportion; the regulation of themotor being effected by varyin'g a valve governing the effectivespeecl'of sa-id motcr, the motor valveregulatin'g variation beingeffected automatically in an inverse direction to the steam pressurevariation, the supplementary regulation being elfected by means ofavalve governing a by-passbetiveen the outlet and inlet of the water feedmechanism, the regulating varia tion in'said: latter valve beingeffectedautomat ically by means of the Water level variations in hedrumLin the same directions said water level variations, and both ofsaid regulations effected slowly and progressively; and being stopped aslight interval after the corresponding regulating factor begins itsreturnmovement towards normal.

4. A process for regulating steam =generators comprising simultaneouslyproviding the feed supply of water, fuel and air for a generator by theaction of a single drive motor-by'nreans'of apparatus having volumetricoutputs substantially proportional to the speed of the drive--motor, ina'proportion corresponding to the exact needs of the generator whenoperating under conditions representing one of the limits'ofefficiencyunder practical operating conditions; automatically regulating the speedof the drive motor through pressure variations in the generator aloneinde-- pendently of Water level variations and without affecting therelative feed of water, fuel'and air to the generator so'as to'inaintainsuch pressure substantially constant and adjusting I the supply of:Water in' relation: to the real: needs: of the 8 generatorandirelative-to thesfeed'of fuel-and air to the generator througli waterlevel variations inthe generator alone= independently or pressurevariations so as to-rnaintain' such -le'vel sub'stan 5 tiaily constant,-the op'erati'on"ofi such regula-- substantiallyconstant, andstartingfr'om the moment at which saidspeed increases above-such saidproportionshall increase-with saidlimit,

speed :ata greater rate'than the speed, and with acceleration inthe-rate'of the increase rising 1 With said speed, the second waterregulation-op oration being :effected by level variationswin thegenerator so as: to maintain such level constant;- 5.- A process for:regulating. steam generators imprising simultaneously providing feed supplies ofl Water; fuel 'and airfor a-generator by the actions ofwasingle: motor'by means of: an

apparatus havingtvolumetric outputs:substantial-- lyvproportional to-thespeed of the drive motor; in aproportion corresponding to theexactneedsof the generator when: operating at its :best 'effi ciency conditions;automatically.regulating. the.

speed of". the drive motor through pressure variations-in'rsth'e'generator aloneindependently of water level variations-andwithoutuaffecting the relativeefeedlof'water, fuel andt'air to' thegeneraton-so; as to. maintain such pressure substantially: constant; andsubtracting the excess of watenin;

the supply 'thus'aproduoed in relationato the .real needsnfthergeneratorandrelative to the fuel and,'airz-feedtoxthe generatorrinorder-ate adapt.

such" supply exactly: *at? all times to such needs;

said subtraction'; beingheff'ected through water-l level variations inthe-generator alone'lindeperr-ldentlyr otpressurewariations so as .tomaintain.

suchleve'lusubstantially constant, the. operation ;of such regulationbeing subject to the direction;

of thevariations of that level, thevcomplementary regui'ationzofj the.supply .of water 1 which is 1 pros in zsaidsprocessrain' responseto thewater;

level .vari'ati'on being effected .Lby means of two 1 different:operations; the first 1 one being governed. by; speed, variations lofthedrive "motor: in a such a Way 'thatxit tends ,to' maintain isaidj sup Iplyjsubstantially. constant as long; asr-thesspeedjrsaiddrivemotor doesnot .reach' double therate corresponding to conditions ofli greatest:ef-l fi'ciency of ;theaboiler,:- and startingg' from. that limitiit.tends :to diminishsuch. supp1y:'as. thespeed-50f the drivemotorrincreases; attaigreater:

rate ofisuoh decrease thanthespeed increase-rate ofthe drive and with anevergreaterzacceleration, the proportion of theratessas the speed ofsaid-1 drive motorincreases the second. regulation be-1 effectedthnoughwatenlevel variations in the generator; so :as to maintain such level.substantiallyv constant.

6. Al process for: regulating steam generators comprising simultaneouslyproviding" thei fe'edzlsupplyzofavater; fuel and 'air'ifo'r a lgenerator by A thesaction: of a single: :driveamotor "by means 0fapparatus having volumetric outputs; substantialis; proportional tothe'speed of the drive motor, in a proportion corresponding to the exactneeds of the generator when operating under conditions representing oneof the limits of efficiency under practical operating conditions;automatically regulating the speed of the drive motor through pressurevariations in the generator alone independently of water levelvariations and Without affecting the relative feed of water, fuel andair to the generator so as to maintain such pressure substantiallyconstant; and adjusting the supply of water in relation to the realneeds of the generator and relative to the feed of fuel and air to thegenerator through water level variations in the generatoraloneindependently of'pressure variations so as to maintain such levelsubstantially constant, the operation of such regu1ation'being subjectto the direction of the variations of that level, the water supply beingproduced by a centrifugal pump, and in order to adjust the supply ofwater from such pump to the exact needs of the generator at all times,variation in the volumetric discharge of the pump is produced byregulation of the discharge cross-l section of water pumped toward thegenerator, such regulation being effected through the differences in thewater level in the generator so as to maintain such level substantiallyconstant, both regulations being effected slowly and progressively andbeing stopped a slight interval after the corresponding steam pressureor water level begins its return movement towards normal.

7. A process for regulating steam generators comprising simultaneouslyproviding the feed supply of water, fuel and air for a generator by theaction of a single drive motor by means of apparatus having volumetricoutputs substantially proportional to the speed of the drive motor, in aproportion corresponding to the exact needs of the generator whenoperating under conditions representing one of the limits of efiiciencyunder practical operating conditions, automatically regulating the speedof the drive motor through pressure variations in the generator aloneindependently of water level variations and without affecting therelative feed of water, fuel and air to the generator so as to maintainsuch pressure substantially constant; and adjusting the supply of waterin relation to the real needs of the generator and relative to the feedof fuel and air to the generator through water level variations in thegenerator alone independently of pressure variations so as tomaintainsuch level substantially constant, the operation of such regulationbeing subject to the direction of the variations of that level, thewater supply being produced by a centrifugal pump, and in order toadjust the water supply from such pump to the exact needs of the boilerat all times, a variation in the volumetric discharge of the pump isproduced by regulation of the discharge cross-section of water pumpedtoward the generator, such regulation being eifected through thedifferences in the water level in the generator so as to maintain suchlevel substantially constant, two outgoing portions of the water pumpedby said pump being varied, such outgoing portions passing through pipesarranged in series; the variations in one of such portions beingregulated by the speed variations of the drive motor itself in such away that as long as such speed does not reach double the speed ofconditions of greatest efficiency of the generator, such portions willremain substantially constant, and starting from that point, as thedrive speed increases, such portion will diminish at a higher rate ofreduction than the rate of speed change of the drive motor and tiallyconstant, both regulations being effected slowly and progressively andbeing stopped a;

slight interval after the corresponding steam pressure or water levelbegins its return ment towards normal.

8, A process for regulating steam generators of the type provided with awater drum-andhaving as auxiliary units a fuel supply mechanism, acombustion air supply mechanism and a waterfeed supply mechanism, whichcomprises thesteps of operating said fuel supply mechanism and said airsupply mechanism as "a group in relation to the water feed supplymechanism and at predetermined relative rates to establish apredetermined proportion between the fuel supply and the air supply,operating all of said mechanisms from a single drive motor, regulatingsaid drive motor in accordance with the steam pressure variations in thegenerator to maintain the steam pressure in said generator substantiallyconstant, and effecting supplementary regulation of the water feed ratein relation to the rates of fuel and air supply in accordance with thewater level variations in the water drum to adapt said water feed rateto the actual efficiency of the generator, and to maintain the waterlevel in said drum substantially constant, said supplementary regulationbeing effected without affecting the rates of fuel and air supply asdetermined by the regulation of said drive motor and while maintainingsaid latter rates at said predetermined proportion, the water feedmechanism being in the form of a centrifugal pump, and the regulation ofthe water pumped being effected by governing a discharge valve on theoutlet of said pump leading towards said generator, said latterregulation being effected through variations in the water level in thegenerator, so as to maintain said level substantially constant, andbeing stopped a slight interval after the water level begins its returnmovement towards normal, the other primary regulation being effectedslowly and progressively and being stopped a slight interval after thecorresponding steam pressure begins its return movement towards normal.

9. A process for regulating steam generators comprising simultaneouslyproviding the feed supply of water, fuel and air for a generator by theaction of a single drive motor by means of apparatus having volumetricoutputs substantially proportional to the speed of the drive motor, in aproportion corresponding to the exact needs of the generator whenoperating under conditions representing one of the limits of efllciencyunder practical operating conditions; automatically regulating the speedof the drive motor through pressure variations in the generator aloneindependently of water level variations and without affecting therelative feed of water, fuel and air to the generator so as to maintainsuch pressure substantially constant; and adjusting the supply of waterin relation to the real needs of the generator and relative to the feedof fuel and air to the generator through water level variations in thegenerator alone independently of pressure variations so as to maintainsuch level substantially constant, the operation '01 such regulation.being subject to -.the direction Y omne variations. of that level,-. theWater .supply being produced by. a centrifugal pump, and in. order-toadjust the. water supply fromsuch pump to .thewexact needs..-of theboiler at all times, a. variationinthe volumetric. dischargeoitheipumpis. produced .byregulationof the discharge cross? section .of water.pumped ..toward the generator,

such.- regulationn being efiectede through the differences in the waterlevel in: the generator so. asitoimaintain such. level substantially.constant, two outgoing portions of the. water .pumped by said pumpbeingvaried,.. such outgoing portions passingthrough pipes arrangedin.parallel; the. variations in vone. .of such. portions .being,regulatedhythe. speed variations-of the drive motor. itself insucha waythat as-longas such speed doesnot reach. double. the speed of.conditions of greatest efficiency of; the generator, such portions willremain substantially constant, and starting fromthat-point, asthe drive:speed increases such portion. will diminish at ahigher rate'of:reducti'onnthan theirate of...speed-.change ofthe drive motor and withcontinuous acceleration inthe relative proportion-of bothcincreasesnsthe motor speed increases; the regulation lof the second. a portion.being effectedhy water level. differences in the generator soas-toimaintain. such levelsubqv stantially. constant,- both regulations1 being effected slowly and progressively and being stoppeda slightintervalafter the corresponding steam: pressure or .water level beginsits return movementtowands normal.

JEAN LOUMIETnr LAVIGNE:

REFERENCES CITED.

The following references aremtrecordeinethe file. of "this patent;

UN ITEDSTA'IES'PATENTS

